Treatment of hydrocarbon oils



Dec 17, 1935. R DAWS 2 @24,68l

TREATMENT OF HYDROCARBON OILS Filed Dec. 11, 1931 r 2 Sheets-Sheet l INVENTOR F56. l

WCHARD F1 DAVIS AT TO RN Dec. 17, 1935. R F DA 2,024,681

TREATMENT OF HYDROCARBON OILS Filed Dec. 11, 1931 2 Sheets-Sheet 2 FURNACE FIG. 2

INVENTOR RICHARD F DAVIS svg j ggigfi Patented Dec. 17, 1935 NETED STATES Feared OFFIQE TREATPLTEN'I OF HYE'RUCARBON OILS Appiicaticn December 11, 1931, Serial No. 580,379

5 Claims.

This invention relates to the treatment of hydrocarbon oils and while not limited thereto refers more particularly to the treatment of low boiling cracked distillates.

5 More specifically the invention relates to the treatment of hydrocarbon oils by chemical means to improve their quality as regards their content of unsaturated hydrocarbons and sulphur compounds, a method of treatment being disclosed which offers distinct advantages over the methods commonly in use in the art for effecting such results.

The selective removal of the more highly unsaturated hydrocarbons and the sulphur compounds from petroleum oils whether of a strai run or a cracked character, is necessitated by the fact that excessive amounts of the former class of compounds render the oils unstable as to color and their tendency to deposit gums and resinous materials and the tendency of the sulphur compounds to impart offensive odor to the products and corrode equipment in which they are used. In the case of hydrocarbon mixtures boiling within the range of commercial motor fuel the presence of excessive amounts of gum-forming constituents renders the fuel unstable because of the tendency of the deposited gums to clog feed lines, carburetors, valves, etc., and the presence of sulphur above a certain amount is especially objectionable from the fact that oxides of sulphur are formed in the burning of fuel and cause corrosion in the crank case.

Sulphuric acid treatment is employed almost universally to reduce the unsaturation and sulphur content of petroleum fractions. The principal disadvantage of this method of treatment lies in the fact that it is difiicult to control its tendency to oxidize, and limit its action to direct combinations with undesirable constituents to produce sludges from which the acid is readily regenerated by hydrolysis. It frequently occurs when acid treatment is conducted to a point necessary for the reduction of sulphur content to 'a certain point that excessive amounts of acid must be used which remove desirable components of the oils such as mono olefins and certain ring compounds along with the sulphur. The present invention is concerned with a method of treatment whereby the necessity for the use of sulphuric acid in treating hydrocarbon oils is substantially if not completely eliminated, treating reactions being substituted which may be controlled to be more definitely selective and which may be applied under a wider range of conditions.

In one specific embodiment the invention com prises treating hydrocarbon oils either in liquid or vapor phase with sulphur dioxide gas in the presence of aluminum chloride.

The reactions characteristic of this method of treatment have been found to produce efiects substantially equivalent to those produced by the use of sulphuric'acid, without the tendency to oxidize the materials under treatment with the production of tarry polymers and sludges from which it is difficult to regenerate the sulphuric acid. The reactions of sulphur dioxide in the presence of aluminum chloride upon unsaturated straight chain compounds produce compounds of the nature of alkyl sulphites and in the case of ring compounds of compounds typified by the sulphinic acids analogous in structure to the well known sulphonic acids but having one less oxygen atom. From sludges containing such compounds the treating reagents are regenerated with 'comparative ease, by regulated heating since the compounds formed are more or less loose addition compounds and altogether the process may be considered as substantially cyclic.

To illustrate some of the applications of the method of treatment comprised within the invention the attached drawings have been provided which represent diagrammatically in side elevation two arrangements of apparatus which may be employed in conducting treatments. Figure 1 shows in essential detail an arrangement of equipment comprising a cracking unit with fractionating and trr ating equipment following and Figure 2 indicates an arrangement which may be employed to treat hydrocarbon oils in substantially liquid phase or while they are undergoing distillation and fractionation.

Referring to Fig. 1, raw oil may be supplied to a cracking unit from a line 1 controlled by a valve 2 to a charging pump 3 which may discharge into line 4 controlled by a valve 5, line l having branch line 6 controlled by a valve 1. The portion of the charging oil discharged through valve 5 may enter a fractionator 2| at some point best suited to properly assist in the fractionation of cracked products by its cooling effect, be preheated and be discharged with reflux condensates through a line 8 controlled by a valve 9. A portion of the raw oil may be discharged through a line 6 controlled by a valve l branching from line 4 and combine with the 50 heated oil in line 8 to enter a line H leading to a combined feed pump is. This pump may discharge through a line it controlled by a valve H into a continuous tubular heating element it disposed to receive heat from a suitable 55 furnace [5 wherein the combined feed is to temperatures necessary for cracking reactions, the heated products passing thr "1 line !5 controlled by a valve ll an enlarged zone typified by reaction chamber is in which the conversion reactions are allowed v :l witnout further application of .eat may be conserved by properly insulat rnber. Such a chamber may provided be and lower removable manhead ll and ll i93 tively to permit acc ss to clean ing out coke deposits and a liquid draw line !9 controlled by a valve 29 for the o intermittent l6lnOl 8- Temperatures p cracking period vary gs nature of the oil cracked though it may be s ate mercial purposes cra J are included within the range or I. pressures between 56 and 598 pounds per square inch.

Vapors from the react on ch wr through a line 59 cont d by a valve into a preliminary fractionator or dephlegmatcr 2! which has been already .neniion-ed. Vapors rally with e results desired for most comfrom such a fractionator may pass through a line 22 controlled. a valve 23 a second-L y fractionato represented by 24 in the drawings,

of a design and type suitable for the product n of overhead fractions of approximate no boiling point range. Such a fract for example, of the so-called bubs.- employed in many distilling processes. in maintaining the proper boiling point range of the vapors issuing from the top of this seco fractionator, a portion of the vapors necessary for recirculation to the top of the tower may be diverted through a line 25 controlled a valve 26 and pass through an auxiliary condenser from which the cooled products pass through a line 28 controlled by a valve 28 to a receiver Such a receiver may have a line controlled by a valve 34' for the transfer of d tilla-te to a pump 33 which discharges into line 34 controlled by a valve 35 back to a point near the top of a fractionator. The admission of vapors to line 25 may be conveniently regulated by the controlled. automatic withdrawal or" gases from receiver 55 through a line controlled by a valve 32.

The portions of the vapors from the secondary fractionator not necessary for use as reflux may pass through a pain vapor line 36 which has interposed there valve 33'. Such vapors which represent approximat the cracked prod-- ucts of gasoline boili lg po t range may be etfectively treated at this 1c prior to their condensation by the method characteristic of the present invention, thus eliminating at once the use of sulphuric acid and the necessity for rerunning of the condensed product. To this end regulated mixtures of sulphur dioxide and aluminum chloride vapors be admitted to the vapor line at a poi from a line controlled by a valve 38. Such vapors ay be pro duced in a generator which a line cor... trolled by a valve 43 for the admission of sulphur dioxide gas, a line it ccu'trolle a valve ll for the introduction of substantially anhydrous aluminum chloride either as a solid or a vapor since aluminum chloride i; without going into the liquid ph "e u" ordinary p essures. Generator 39 may loo V. W heate f necessary to produce ready volatinzation of aluminum chloride and insure the generation of properly proportioned mixtures with sulphur dioxide which are then passed into line 31. The oil vapors and treated materials may then be passed into a recticn chamber and separator 44 in which the treating reactions are completed and the sludge separated, the latter being withdrawn continucusly or intermittently through a line 45 controlled by a valve 55. It may be advantageous under certain circumstances to add additional amounts of the sulphur dioxide-aluminum chloride vapor mixture to the treating chamber and to permit this, a line 3'. controled by a valve 38 may be provided connecting line 31 directly with reaction chamber 44. treated vapors from the reaction chamber may pass through a line 4'! controlled by a valve 48 and have such vaporous acidic constituents as may result from the preceding treatment neutralized by alkaline gases such as ammonia or aqueous solutions such as caus ic soda introduced from a l ne 49 controlled by a valve 50 at a point B, additional amounts of neutralizing reagents being added to the separator 5! arough a branch line 49 controlled by a valve 58' if found necessary. Separator 5! may be provided with a draw line 52 controlled by a valve 53 for the removal of liquid or solid accumulations.

Neutralized. oil vapors emerging from separator 5! may through a line 54 controlled by a valve filt ring material such as fullers earth, sand, finely divided clays, etc, for the removal of treat-- ing reaction products. A line 5'! controlled by a valve may be provided to admit steam or other gases at a point C in line 54 or into the top of the filter chamber from a branch line 54 controlled by a valve to control the rate of passage of the vapors through the stationary filter m. or at times to wash the same free from adhering impurities.

Treated vapors, after passing the filter bed, may be conducted through a line 59 controlled by a valve 66 to a final fractionator 6! capable of producing treated end product vapors and simultaneously removing heavy portions which may have resulted from. polymerization reactions in the preceding treating zones. The vapors from such a iractionator may pass through a line 59 controlled by a valve "ill and be cooled in a condenser "H, the cooled products passing through line 52 controlled by valve l2 and entering a receiver M provided with a line l5 controlled by a valve for the release of gas and a line H controlled by a valve 78 for the removal of treated gasoline to storage. in connection with the sccondar tower of the crack imit, a portion of the treated gasoline may e returned to the top of fractionator 5! for controlli the boiling point range, such portions being transferred to a pump 8! through a line it controlled by a valve 53 and discharged through a line 82 controlled by a valve 83.

tton s from fractionator 6! may pass through .ne controlled by a valve $35 to a receiver which also receives bottom liquids from filter mber 5E through a line 6?. controlled by a valve To prevent vapor lock, line 51 controlled by a valve r. be provided connectspace o er with the fracator Si. Fractions soiling above he desired .lge in the finished gasoline may be returned to the secondary tower of the g system by means of a pump which withdraws such fractions from receiver 84 through a line 8 and a and enter a chamber 56 containing As previously described Lil) iii)

valve 85 and discharges them into a line 81 controlled by a valve 88.

The preceding description was concerned with a method of treating cracked vapors of approximate gasoline boiling point range with the reactions characteristic of the invention prior to their final rectification.

In Figure 2 an apparatus capable of effecting treatments in substantially liquid phase is shown which consists of a treater I I5, a heating element I07 disposed to receive heat from a furnace I08, a condenser I33 which may return a portion or all of the condensed liquids to the treater and means for admitting the treating reagents, circulating the liquids being treated and disposing of reaction products.

Line I! controlled by valve I02 indicates a line through which hydrocarbon liquids to be treated may be introduced into a line I03 on the suction side of pump I04 which discharges into a line I05 controlled by a valve I05 leading to heating element III? or into branch line I09 controlled by valve H0 which by-passes the heating element. Line I09 makes a junction with line III at the exit of the heating element and either heated or cold liquids may be added to the treater by the use of valve H2 in this line or through a branch line H3 controlled by a valve H4 which typifies a line provided at some level below the top of the treater.

Treater I I5 may be of any type suitable to the purposes of the treatment such as a cone-bottomed agitator preferably gas-tight or a fractionating column of some variety. A manhead H6 may be provided to permit entry to the treater and line I 29 controlled by a valve I30 may be provided for the admission of treating agents characteristic of the invention. Line H6 controlled by valves HI and H8 is shown leading from the bottom of the cone of the treater and may be utilized to withdraw residual accumulations for ultimate disposal or for the circulation of only partially spent reagents, in which case valve I2I may be opened and valve H8 closed and the materials returned through line I03 to the circulating pump I04. In operations involving the continuous removal of sludge and at the same time circulation of the oil undergoing treatment, a line I I9 controlled by a valve I may be provided which takes suction on the treater at a point above the level of the sludge and leads to line I 03. To permit the admission of sulphur dioxide to the suction side of the oirculting pump a line I22 controlled by a valve I23 may be provided and for the introduction of aluminum chloride in a concentrate or slurry in more or less non-reactive suspension mediums, a line I24 controlled by a valve I25 may lead to a pump I26 which discharges such suspensions to a line I21 controlled by a valve I28 into circulating line H9 leading ultimately to the suction side of the circulating pump.

The equipment thus far described may be utilized in a variety of ways, the oils being treated either cold or at suitable superatmospheric temperatures. For example, cold oil may be charged to the treater, finaly divided anhydrous aluminum chloride added through the manhead I I6 or by means of pump I26 and treatments conducted by merely introducing sulphur dioxide from line I29, suitable distributing means being employed to effect good contact and the introduction of the gas serving to maintain the chloride in suspension. In such an event evolved gases may be discharged through the vapor line I3I from the top of the treater and pass through a valve I32 in this line for suitable disposal. In other cases where the optimum temperature of treatment is above atmospheric, the contents of the agitator or treater may be gradually brought to the desired 5 temperature by circulating through heating element I01, the reagents being added gradually to produce the desired treatment and the sludge drawn at the completion of the treatment. Such a treatment may be conducted under superat- 10 mospheric pressure necessary to prevent substantial volatilization of the oils undergoing treatment or under substantially atmospheric pressure with refluxing of the volatilized constituents. In such a case the lighter and more 5 volatile portions may pass through a condenser coil I33 which has an outlet line I34 controlled by a valve I35 and a branch line I4I controlled by a valve I42 leading back to the treater.

Continuous treatment may be conducted by n utilizing the treater as a fractionating column in which case the oil to be treated and the treating reagents are added continuously, the combined fractionator and treater producing end product vapors which are collected in receiver I36 and 25 sludge and heavy liquids which are drawn from the system through line H6 by the manipulation of valves II! and H8. Receiver I36 may be provided with line I31 controlled by a valve I38 for the release of gas accumulations and line I39 30 controlled by valve I40 for the removal of treated liquids.

While the treatment characteristic of the invention may be used advantageously in many instances without any other type of treatment, it 35 is intended to include in the invention the use of this treatment in conjunction with other commonly known methods of treatment such as treatments with sulphuric acid of varying strength, caustic soda, fullers earth and other polymeriz- 4o ing reagents. Notable eflects may be observed when other volatile metallic halides, for example, stannic chloride, boron fluoride, etc., are substituted for aluminum chloride uniformly mentioned in the description.

As an example of results obtainable by a vapor phase treatment comprised within the scope of the invention, the case of cracked vapors from a unit running on 24 gravity fuel oil may be mentioned. These vapors may be treated according to to the method described in connection with Figure 1 by sulphur dioxide gas at the rate of 2%, pounds per barrel of the treated gasoline produced, there being used also aluminum chloride at the rate of approximately 1 pounds per barrel. The finished gasoline produced by this treatment at the temperature of the vapors from the secondary fractionator (which may be in the neighborhood of 375 F.) may possess all the characteristics required in commercial motor fuel, 69 to wit, a color of over 25 on the Saybolt scale, gum content of less than 25 mgs. as determined by the copper dish method and a sulphur content of approximately 0.1%.

As an example of a liquid phase treatment, a kerosene distillate from a California crude may be treated at a slightly elevated temperature, for example, F. in an apparatus similar to that described in connection with Figure 2. Finely divided aluminum chloride at the rate of approx- 7 imately 2 pounds per barrel of oil treated may be added to the oil in the agitator and sulphur dioxide introduced during circulation of the oil and chloride at the rate of 10 pounds per barrel. The distillate prior to such a treatment may have 7 5 a B. gravity of 38 and possess objectionable color and odor in addition to having very poor burning qualities in the customary lamp tests; By treatment to exhaustion of the reagents used in the amounts mentioned such a distillate may be brought to practically water white color with a raise in gravity to 40 B. with sufiicient increase in burning properties to render the oil saleable as a commercial kerosene.

While the foregoing descriptions and examples have served to indicate toa certain extent some applications of the process of the invention, it is to be understood that they are given for illustrative purposes only and are not to constitute a limitation upon the generally broad scope of the invention.

I claim as my invention:

1. In the refining of hydrocarbon distillates containing unsaturated hydrocarbons and sulphur compounds, the step which comprises treating the distillate with sulphur dioxide in the presenceof aluminum chloride.

2. In therefining of normally liquid hydrocarbon distillates containing unsaturated hydrocarbons and sulphur compounds, the step which comprises treating the distillate in vapor phase with a mixture of sulphur dioxide gas and a metallic halide catalyst which is vaporized at the temperature of the hydrocarbon vapors.

3. In the refining of hydrocarbon distillates containing unsaturated hydrocarbons and sulphur compounds, the step which comprises treating the distillate in vapor phase with a mixture of sulphur dioxide gas and aluminum chloride vapors.

4. A process for refining cracked gasoline which comprises contacting the same with sulphur dioxide gas in the presence of aluminum chloride.

5. A process for refining cracked hydrocarbon vapors of motor fuel boiling range which comprises contaoting the vapors with sulphur dioxide gas in the presence of aluminum chloride 20 vapors.

RICHARD F. DAVIS. 

